Brian Castner arguably had one of the most nerve-wracking jobs in the U.S. military. He commanded two Explosive Ordnance Disposal units in Iraq, where his team disabled roadside IEDs, investigated the aftermath of roadside car bombings and searched door to door to uncover bomb-makers at their homes.

"We would disassemble the IEDs when somebody else found them; we would go on route-clearance patrols with the engineers to trip the ambushes before they would hit our convoys; and we would do the post-blast investigations," Castner tells Fresh Air's Terry Gross. "Hopefully we would find weapons caches and dispose of a lot of this bulk ordnance before it would be used as an IED. ... But there was no getting rid of all of the bombs."

Sometimes those bombs would go off and Castner's team would be responsible for investigating the gruesome aftermath.

"You would show up and the loved ones would already be picking up bodies or pieces of bodies and they're already loading the destroyed car onto a flatbed, and it's bad enough that you're out there doing this but they're getting in the way of you doing your job," he says. "We could be there for 10 minutes. Because the longer you're there, the more chance you have to get shot at or have a mortar dropped on your head. So you get out as quickly as you can."

In his memoir, The Long Walk, which is currently being adapted as an opera for the American Lyric Theater, Castner chronicles his three tours in Iraq and the life that followed when he returned home as a different man, unable to forget what he saw or experienced in Iraq. He describes his experiences as "Crazy" — a term that is often repeated in the book.

"You don't want to be a caricature of yourself but that's what it felt like I was turning into," he says. "And I needed a word [for it]. And if you're nauseous, you know you're about to throw up and if you have a headache, that's called pain. But I had a physical symptom that I didn't have a name for. ... So 'Crazy' was the best way to describe it."

Castner also had physical symptoms in addition to the problems in his mind. He began experiencing cognitive side effects related to his close exposure to blast attacks. In recent years, he was diagnosed with traumatic brain injury. Long-term-memory problems, hearing issues and sleep apnea have plagued his body.

"The one that really bothered me, by and far, is the long-term-memory loss," he says. "I've got some sections of when my kids are younger and when my wife and I met and really the first three-quarters of my marriage that I simply don't remember. ... That was part of what I was working through [when I wrote the book]. Why can I remember the day of six [car bombs] so well but I can't remember my kids being born?"

Interview Highlights

On transitioning to home life

"The stakes were all too low suddenly. Whether I did the dishes or not didn't seem to rise to the challenge of what I had done before. When nothing is important anymore, everything is important. Little things start to become too important and you start to become obsessive over the details. And that obsessive part of my brain that kept me alive in Iraq went into overdrive and it became the hindrance. It got in the way."

On why soldiers tie their ID and blood type around their feet instead of their hands

"It turns out that you put your blood type and your NKA (no known allergies) on my foot and you stick a dog tag in your laces because it's the part of you that's most likely to survive if you get blown up. We found feet a lot. If you're going to find a part of the bomber or victim, you might find their head. It's a better chance that you're going to find their hands and feet."

On arriving at the scene of an IED after it went off

"You become numb to it eventually. But I would never call it business as usual. And in fact, the post-blast mission is one that only really developed as the war went on. When I initially went through EOD school, there was no section of the training that was called post-blast investigation. On my first trip to Iraq in 2005, the first time I did one, I had to ask, 'Well, what does that even mean? What do you want me to look for?' "

On the long, lonely walk that was also portrayed in the 2008 film The Hurt Locker

"I put guys in suits all the time and I gave them the approval to put on the suit and go down nearly every day. And it is certainly the longest, loneliest walk that you will ever take. For an EOD guy who is used to being in control and accomplishing the mission, it is certainly more terrifying to be the one in the suit. But not having the sense of control to be the one used to just drive me nuts — to watch them walk down. Neither I nor anybody else can help them in that moment."

On giving the command to shoot a man who he thought might be triggering an IED

"It does not weigh on me because we made a mistake because mistakes happen in wartime. Everybody's just doing the best they can to survive every day. And so I don't regret it from that perspective. I felt like I wanted to give Trey [who was in my unit] the cover to do what he needed to do [which was disarm a potential bomb in a car] because I felt like that was my responsibility. If something bad happened, I wanted to have whatever was going to happen land on me instead of him. If there was an investigation or if there was some sort of wrongful death inquiry, I wanted them to come talk to me.

"But what really bothered me about that situation was [that] I had told myself that what we were doing in Iraq was keeping everyone alive. We kept U.S. soldiers alive, we kept Iraqis alive, we took apart every single bomb and it didn't matter who the target was — it didn't matter if it was going to blow up an Iraqi school or a U.S. convoy. You take them all apart. And in this situation, we were going to use our explosives to kill somebody instead of making Iraq just a little bit safer."

Copyright 2013 NPR. To see more, visit http://www.npr.org/.

Transcript

DAVE DAVIES, HOST:

This is FRESH AIR. I'm Dave Davies, in for Terry Gross. Being exposed to car bombs and IEDs of every sort was a way of life for our guest, Brian Castner. He was the commander of an EOD unit in Iraq. EOD stands for explosive ordinance disposal. His unit's mission was to clear roads, cities and buildings of IEDs, find and blow up weapon caches squirreled away throughout the country, and collect evidence from blast scenes to track down and kill the bomb-makers.

He had robots to defuse IEDs. But when the robots couldn't get the job done, one of the men had to put on the 80-pound, protective Kevlar suit and take the long walk to the bomb, the real version of what was depicted in the film "The Hurt Locker."

Castner's memoir, called "The Long Walk," is now out in paperback. It's about his experiences in Iraq and the after-effects of being exposed to constant stress, life-threatening risk and hundreds of explosions. Among the things he's dealing with is traumatic brain injury. Castner was an officer in the Air Force from December 1999 to September 2007.

Castner was an officer in the Air Force from December 1999 to September 2007. He says his memoir is as correct as it can be from someone with blast-induced memory lapses. Terry spoke with him last year, when "The Long Walk" was published.

TERRY GROSS, HOST:

Brian Castner, welcome to FRESH AIR. You know, reading the book, I just kept thinking that you not only had one of the most nerve-wracking jobs imaginable, being in, you know, being in the unit that has to dispose of the explosives and take them apart, make sure that they're not going to explode; but it's also the most gruesome job because you're going to the site of IED explosions and looking for evidence.

You're dealing with liquefied body parts. You found an intact colon. You describe the pink mist of blood that hangs over the explosions, and I just can't imagine how you deal with the stress of the job and then the gruesome aspect of it, and I guess you feel like you just went crazy from it after a while.

But I'm not even sure what my question is because I think it's such an overwhelming experience to have had. So, did it ever become business as usual, or was it always just horrifying?

BRIAN CASTNER: You become numb to it eventually, but I would never call it business as usual. And in fact, the post-blast mission is one that only really developed as the war went on. When I initially went through EOD school, there was no section of the training that was called post-blast investigation.

And in fact on my first trip to Iraq in 2005, the first time I did one, and I got tasked, and they said go out and do an investigation, I had to ask, well, what does that even mean? What do you want me to look for?

So as the war developed, and as the IEDs, the improvised explosive devices, became less just an obstacle to clear and were more a focus of the war, our career field developed those skills as we went.

GROSS: So what kind of evidence would you look for at the site of an IED explosion?

BRIAN CASTNER: Anything that would tell you how it was made, what the target was, if there was a key identifying feature that would link it to one bomber or another, or one group or another. So that's anything from the color of the wire used to connect the battery to the blasting cap, to getting an explosive sample of the type of explosives used, to collecting the VIN number on the car, to getting DNA samples of the people who were there so maybe you could identify which one the bomber was.

GROSS: But this isn't like going to, like, a crime scene after the fact, where you're slowly getting evidence and putting it in plastic bags. You are going to the site of explosions, and there are screaming people all around you, and you're going through body parts, basically, like looking for evidence of what happened in the explosion.

And take one of those experiences, for us, and just describe what the experience was for you.

CASTNER: Right, so you get the call, and you're at your home base, at the FOB, and sometimes we wouldn't even need a call, you would see the towers of black smoke rising from downtown Kirkuk. And you know the call is coming, so you go and get ready. And you get out there as fast as you can, which is usually about 20 to 30 minutes after it went off.

CASTNER: And we actually didn't want the Iraqi police or U.S. forces to clean up. We needed everything there to be able to sift through. And in fact that would be the most frustrating part is you would show up, and the loved ones would already be picking up bodies or pieces of bodies, and they're already loading on the destroyed car onto a flatbed.

And it's bad enough that you're out there doing this, but they're getting in the way of you doing your job. And so extremely quickly, we could be there for 10 minutes because the longer you're there, the more chance you have to get shot at or have a mortar dropped on your head or something. So you get out, and as quickly as you can, starting at the burned-out car and then working your way out, you just look for everything you can.

And sometimes, in fact, you're looking for pieces of ordinance that haven't exploded. An artillery round will kick out, and it'll be in somebody's house a block away, and you need to grab that and make sure you dispose of it so nobody gets hurt.

GROSS: So give us an overview of what your job was as a member of the Explosive Ordinance Disposal Unit, the EOD.

CASTNER: Sure. So all four services - Army, Navy, Air Force, Marine Corps - we all go to the same school, and we all get the same basic skills. And so we're pretty much interchangeable when it comes to a war like Iraq or Afghanistan. So I was in the Air Force, but I was supporting the 101st Airborne Division, for example, in Kirkuk.

And we would disassemble the IEDs when somebody else found them, we would go on route-clearance patrols with the engineers, which is just driving the main highways looking for IEDs and trying to get shot at, essentially, to trip the ambush before they would hit our convoys.

We would do the post-blast investigations. Hopefully we would find weapons caches and dispose of a lot of this bulk ordinance before it even made it out to be used as an IED. But Saddam Hussein and the Iraqi government bought so much ordinance over the years, there was just always more. There was no getting rid of all of the bombs.

GROSS: A lot of our listeners will know about the work that you did through the movie "The Hurt Locker," which I'm sure had some truth and fiction mixed together about the job. But, you know, the most dramatic thing in that film was when somebody had to put on, like, the suit, the 80-pound Kevlar suit and do, you know, the long walk to the actual bomb and then try to disassemble the bomb before it exploded. Did you ever have to wear the suit and do the walk?

CASTNER: You know, I never did. And as an officer and in command of the unit, I went on lots and lots of missions, but it was definitely the team leader, the specialist who has done nothing but the technical aspect of the job for a decade. You know, it was his job to put on the suit.

So I put guys in suits all the time, and I gave them the approval to put on the suit and go down nearly every day, every other day. And it is certainly the longest, loneliest walk that you will ever take.

For an EOD guy who is used to being in control and accomplishing the mission, it is certainly more terrifying to be the one in the suit, but not having the sense of control to be able to do the one, used to just, you know, drive me nuts, to watch them walk down. And really, neither I nor anybody else can help them in that moment.

GROSS: Did any of the men you work with actually get killed wearing the suit and doing the long walk to disassemble a bomb?

CASTNER: I was extremely lucky. So nobody under my direct command did while I was commanding them or while I was in charge. I have lost a lot of friends who were in the suit. I have lost a lot of friends who were not in the suit because they never had a chance to put it on because something blew them up that they didn't see.

But I'm - I consider myself extremely fortunate that I was never in the position of saying yeah, it's time to put it on and then to see them turn into that pink mist cloud that you talked about.

GROSS: What did you wear yourself?

CASTNER: When we got started in Iraq, guys were putting on all sorts of combinations of hillbilly armor we called it. You bolted on metal plates to the side of your soft-skinned Humvee. And eventually the armor got so, so good, guys are really surviving blasts that they never would have before.

And when - I just went down in May to the EOD Memorial. We have a memorial in Florida in Fort Walton Beach, and there's a wall set up where we put all of the names of the guys who died in the last year. We have the annual ceremony in May, and then all of the names for everyone since World War II is on there.

And when you go to that ceremony, what strikes you is not just the number of names that we're putting on, which was 18 last year, which was the most since 1945, but then also that the other guys who are there attending, the number of people that have missing limbs, missing arms, missing legs, they probably would have died in previous wars, but the medical apparatus or infrastructure I should say that we have now is so good, people are losing multiple limbs, and they're coming home alive.

DAVIES: Brian Castner, speaking last year with Terry Gross. He was the commander of an explosive ordinance disposal unit in Iraq, the units which would disassemble and diffuse IEDs. His memoir, "The Long Walk," is now out in paperback. We'll hear more after a break. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: If you're just joining us, my guest is Brian Castner, and he's written a new memoir called "The Long Walk: A Story of War and the Life That Follows." He was the commander of an EOD Unit in Iraq, that's explosive ordinance disposal, and it was his team's job to disassemble IEDs, also to go to the scene of explosions and try to get as much evidence as possible.

It was an incredibly dangerous job and an incredibly gruesome job because they were exposed to so many explosions and body parts and grief. Let's talk about one of the worst days for your group, and that was the day you describe as the day of the six VBIEDs, and VBIED is V-B-I-E-D, that's a vehicle-borne IED. So is that a car bomb that we're talking about? Is that basically a car bomb?

CASTNER: It is. Of course the military has an acronym for everything.

GROSS: Yes.

(LAUGHTER)

CASTNER: And so there were many kinds of IEDs, and they would just put different letters in front of them to differentiate, but car bomb is exactly right. We had six in 15 minutes. Five of them detonated, and one did not.

GROSS: OK, so that was a bad day, the day of the six car bombs. But you say the next day was even worse. Describe what happened the next day.

CASTNER: We actually had three days that were really bad, and this might tell you something about the nature of memory or how mixed up it all was in my mind. I didn't realize that these three days happened in succession until the book was nearly done, and I was looking through some of my old journals.

But on the first day, we did a raid on what we thought was an EFP factory, and it turned out not to be, in an Arab part of town. The next day, we had the day of six VBIEDs, and then the third day we were so amped up and ready for more that we had another VBIED, but it didn't - it never felt right from the beginning.

A vehicle rammed a U.S. convoy, which was not their normal tactic, and when the team got out there, Trey(ph), who was the team leader, he's a reservist, he's a cop, he's got a lot of experience in dealing with crowds and stressful situations, but I could tell something wasn't right. He was taking a lot of gunfire.

It happened at the central roundabout just south of Kirkuk, where a lot of different highways come in. So he was extremely exposed, getting shot at a lot. And as he was trying to take this bomb apart, he realized that the driver, who was shot, wasn't dead. And more than the fact that he wasn't dead, he refused to get out of the truck.

And so we got to a point, which is the situation that you really don't want to see or that we dread seeing, which is that one of our explosive tools, which is supposed to be used to disassemble a bomb to make it safe, we were going to be in the position of having to use it on a person. If he didn't get out of the truck, we were going to have to blow it up with him in it.

GROSS: Why couldn't you just drag him out of the truck?

CASTNER: Well, that would involve taking the long walk again. We - and in fact, Trey went up and tried - he thought maybe the individual was pinned and couldn't get out of the truck. And so there was an interpreter over a loudspeaker that was trying to get the driver to leave, and he wouldn't leave, he refused. So Trey thought maybe he's stuck. He runs up there to try to see if he's stuck, and it turns out he's not.

He was simply being stubborn, or he was scared, or he didn't understand. And so at that point, if he refuses to leave, and Trey thought he saw an artillery round in the front seat, if we confirm that there is an IED inside, it's just a dangerous situation for everyone. You have to safe the IED, and you can't just leave it.

GROSS: Is it fair that he'd be wired, too, that he was, you know, maybe a suicide bomber who had explosives on his person?

CASTNER: Well, we had six suicide bombers the day before. And why would he ram a U.S. convoy? The whole situation was just very, very odd. And as we think - as I think back now, I wonder if there really was a bomb inside, because what eventually happened is once Trey put the explosive underneath the truck, once the guy saw that the robot was putting this thing underneath him, he did get up, but he didn't follow any directions.

He didn't follow the commands of the interpreter, and he started putting his hands up underneath his clothing to activate what Trey thought was a bomb. So we had to shoot him. And as it turns out, there was nothing on him. And it's - and so it's decisions...

GROSS: The thing he was reaching for, apparently, was his Quran.

CASTNER: Correct. He was - why was he walking to the crowd without stopping? Why was he reaching for it? I don't know. Was he planning on stopping to pray at that moment? I simply don't know.

GROSS: My impression from the book is that this experience really weighed on you because you had to give the command to shoot him. And it's something you really didn't want to do, is my impression. You called your captain and asked him what do we do, we don't want to kill this guy, but he's not going to get out of the car.

And the captain told you that, well, military had already tried to kill him and shot him at least once, so, you know, basically do what you have to do. But then he gets out of the car, and you have to give the order to shoot. At the risk of stating - of asking the obvious, why has that weighed on you so much?

CASTNER: It's - it has not weighed on me because we made a mistake because mistakes happen in wartime. Everybody's - everybody's just doing the best they can to survive every day. And so I don't regret it from that - from that perspective. I felt like I wanted to give Trey the cover to do what he needed to do because I felt like that was my responsibility.

If something bad happened, I wanted to make it - I wanted to have whatever was going to happen land on me instead of him. If there was an investigation, or if there was some sort of wrongful death inquiry, I wanted them to come talk to me.

But what really bothered me about that situation was I had told myself that what we were doing in Iraq was keeping everyone alive. We kept U.S. soldiers alive, we kept Iraqis alive. We took apart every single bomb, and it didn't matter who the target was. It didn't matter if it was going to blow up an Iraqi school or a U.S. convoy, you take them all apart.

And in this situation, we were going to use our explosives to kill somebody instead of, you know, making Iraq just a little bit safer.

GROSS: You wore your ID and your blood type around your foot, around your ankle. Why is the foot a good place for that? This is something that you learned in ways that no one would want to learn.

CASTNER: Right, so it turns out that you put your - I put my blood type and NKA, no known allergies, on my foot, and you stick a dog tag - or on my boot, I should say, and you stick a dog tag in your laces because it's the part of you that's most likely to survive if you get blown up.

And so we found feet a lot. If you're going to find a part of the bomber or a part of the victim, you might find their head. It's a better chance you're going to find their hands and feet.

GROSS: Why is that?

CASTNER: Well, on a suicide bomber, certainly, it's because the explosives are around their chest, and so the torso goes away, but the rest of you remains. In Iraq, there weren't as many explosives that would - or IEDs, I should say, that would trigger from stepping on them. That's the big hazard in Afghanistan.

We had a lot of other kinds of IEDs, like the EFPs they would shoot through your vehicle, and if that happened, it would - depending on where it would hit - you would often lose your leg, you'd lose an arm, it would go through your head or chest, and you would bleed out.

But there was a pretty good chance that your feet would still be there. So even if the rest of you went away, you know, that part would remain.

GROSS: Has this changed your feeling about your feet?

(LAUGHTER)

GROSS: I'm even wondering, like, if you still keep an ID on your feet because it's been so hard for you to give up some of the habits of the war.

CASTNER: That's true. That's one that I have - I guess that's - now that I think about it, that's one that I have given up. I don't - I take care of my feet. I go running a lot, and so I have very good running shoes now. And in fact maybe this is more symbolic than I realized: The place where I used to keep my dogtag in the laces is now where I have the foot pod that keeps track of all of my miles from running.

And I run 15, 18 miles a week and religiously keep track of my times and mileage, and the running has been part of helping me come home. So maybe there's something to that.

DAVIES: Brian Castner, speaking last year with Terry Gross. We'll hear more in the second half of the show. Castner's memoir "The Long Walk" is now out in paperback. I'm Dave Davies, and this is FRESH AIR.

(SOUNDBITE OF MUSIC)

DAVIES: This is FRESH AIR. I'm Dave Davies in for Terry Gross. Let's get back to our conversation with Brian Castner. He commanded an Explosive Ordinance Disposal - an EOD unit in Iraq. His team's mission was to clear roads, cities and buildings of IEDs, disassemble them to render them safe, find and blow up weapons caches and collect evidence from blast scenes that could be used to track down the bomb-makers.

He returned home a different man - nerves shot, memory lapses, feeling kind of crazy. He was eventually diagnosed with traumatic brain injury. Castner's memoir, now out in paper, is called "The Long Walk." Terry spoke with him last year.

GROSS: How many blasts would you say approximately that you were near in Iraq?

CASTNER: I have about five or 10 that I would say I was way too close. And then I have another couple dozen that were probably too close enough that they did a little bit of brain damage. And then on average we would blow something up or something would blow us up about two or three times a day. So I guess the total number is in the hundreds, maybe a thousand.

GROSS: Wow. So you always thought you were lucky for surviving - had your limbs, nothing blown off, no blood, no wounds. But after you came home you realized the kind of permanent damage that exposure, sometimes very close exposure, to all those blasts had really caused. What's your understanding now of how exposure to those explosions affects your brain?

CASTNER: So there's been a lot of new research, and this is not something that anybody could've told me 10 years ago because we didn't have the research to tell us this because so much of it is so recent that you can - your brain is damaged by simply being close to an explosion. And there's really two kinds of brain damage when you think about traumatic brain injury, TBI, which is a bit of a buzzword now. Fortunately, people are becoming more aware of it. There's the concussion problem, which is what happens to football players and hockey players and boxers, and it happens to soldiers too. And that's when your brain comes to a sudden stop and smushes on the inside of your skull. And that happens in traffic accidents and such.

But then there's a more insidious part, which is that explosive waves are a lot like sound waves, they're compression waves. And so when they travel through a medium, they speed up or slow down, depending on how dense that medium is. So they move relatively slowly through the air and then they speed up say through the wall, or they speed up through a car. They also speed up through your head. Anywhere that there's a change in density there's going to be sheer ripping forces and tearing forces. And we always knew about these because that's what causes a lot of the deaths from suicide attacks or from terrorists attacks, is there's a phenomenon called blast lung, and that's when the overwhelming blast tears all those little air pockets in your lungs and you essentially drown on your own blood.

Well, all those forces that would've ripped all of that up also do the same thing in your brain. Every nerve ending and little fiber and little bump and nodule starts moving at a different speed as that blast wave moves through your head and so you tear things internally. And if you go through a single traumatic event, if you step on a land mine or an IED and you lose your leg and that detonation is so close, you can have a single instantaneous traumatic event that does a lot of damage. But if you blow something up every day, it's more like occupational exposure. It's like playing guitar too loud in a band for years, except you're not just losing your hearing, you're losing short-term memories, you're losing and long-term memories, you're losing the ability to make decisions, there's sleep apnea problems that come from it, a lot of sleep disorders. There's just a lot of little insidious things, and it's a spectrum of problems and I'm very lucky that I'm on one end. But all of my brothers in the EOD world, we all have some variety of this from having blown so many things up over the years.

GROSS: What variety do you have?

CASTNER: I have sleep apnea. I have restless leg syndrome that I thought was, I thought it was a fake disease. I thought it was something that people made up just to sell drugs and, you know, and sell pharmaceuticals on commercials until I had some knee surgery and I started - my legs started twitching and I really felt it because every time I leg moved while I was sleeping it would come up.

The one that really bothered me, by and far the most problematic one is the long-term memory loss, is I've got some sections of when my kids were younger and when my wife and I met and really the first three quarters of my marriage that I just, you know, my wife says do you remember that third birthday party? No, I simply don't. And in fact, I don't remember months on either side of it either.

GROSS: But you remember your experiences in Iraq and remember them well enough to have written the book?

CASTNER: That's the really frustrating part. That's the, and that was part of what I was working through, is why can I remember the day of six VBIED so well but I can't remember, I can't remember my kids being born?

You use the word crazy a lot in your memoir, describing how you feel crazy. And crazy is almost like a state of being. I mean, you're almost like; it almost becomes a character in your book. And it's a funny word to use in a way because I think a lot of vets coming home, the last thing they want to be called or thought of as is crazy. Why did you want to use that term so much to describe how you were feeling?

Well, one reason is the reason you just gave is because it did feel like something outside of me. But I know well the stereotype and I feel it myself. You just don't want to be the crazy veteran. You don't want to become a caricature of yourself. And that's what it felt like I was turning into, and I needed a word. And if you're nauseous, you know you're about to throw up. And if you have a headache you know that that's called pain. And you probably know what stress is and worry is, but I had a physical symptom that I didn't have a name for. And I went to the emergency room a couple times because I thought I had a heart attack, and it turns out I didn't. And they hooked me up to all the tests and stress test and everything else and when they eliminated every physical symptom or every physical potential, I was left with a feeling that still didn't have a name. And so, crazy was the best way that I could describe it.

GROSS: I want to describe something that you write about that I found very disturbing. And you're talking about how when you're home and, you know, you're just kind of like paranoid and thinking of yourself as crazy and having all these physical symptoms as well. And you describe wanting to strap a pistol to the center console of the family minivan. And I thought that's just...

(LAUGHTER)

GROSS: ...that's scary. I mean, you have kids, who'd be driving in that family minivan. Just tell us what was going through your mind and how far you got with a plan.

CASTNER: Well, I can understand how you would call it scary because my children were there. That's why I wanted it because I needed to protect them. I don't know what I needed to protect them from. I had seen so many dismembered children in Iraq that I, as a father, I really felt the need to protect them from something and this was how I knew to do it. And it's how I knew to make sure that I felt safe and they would be safe. And I have no idea who I was planning on shooting. I wasn't planning on shooting anybody. It was just the way my mind and the planning dealt with it. So I never, I never did get to actually putting it into a minivan. New York state gun laws are pretty restrictive. I was never seeking to break the law. But I did use my muscle memory, which is when you shoot your pistol and your rifle enough you just it's kind of ingrained in your body of how to do that. So I used the skills I already had to learn how to reload with one hand, which actually isn't that hard if you just put the magazines in a certain place you can pop the open pistol grip down over it and it'll latch on and you can slide the bolt forward and you'll be ready to go.

GROSS: So you still had a gun with you that you could use one-handed?

CASTNER: Well, the pistol is the thing you can use one-handed because you just can't shoot a rifle and drive at the same time. It doesn't work.

GROSS: So you were carrying.

No. Well, I don't have a concealed carry so, no, I wasn't carrying a pistol everywhere I went. I felt like any time I was in a public situation or I was starting to feel threatened by a crowd, I felt, I mean, I could feel it on my fingertips. Obviously, it's not actually there, but it's what brought comfort is knowing that, knowing it was there if I needed it or knowing that I knew the right thing to do even though - you know, there's a scene in the book where it used to happen in airports a lot for some reason, where I would start to feel trapped and then the way my brain deals with that is how am I going to leave the situation and basically who do I have to shoot between me and the emergency exit to get there?

CASTNER: Because as an EOD guy, we weren't kicking down the door first on raids. If we were going to have to shoot our way out of a situation it was because our security was overwhelmed or dead, and so a lot of our training was focusing on extricating yourself when something really, really bad has happened. So I would start to feel lots of people in the airport and my security is not there and so who do I have to shoot to get out of here safely is what would just run through my head. And there's a little part of my brain that knew that normal people don't plan these kinds of things. And just knowing that just, it bothered me on an additional level.

GROSS: So just so I understand fully, when you would feel the pistol on your fingertips, that was an imaginary pistol that you weren't really carrying?

CASTNER: Right. It - well, yes. I swear to you, I can feel it. But it's obviously it's all in my head. No, I wasn't actually - I made a lot of plans about what to do and I fortunately for everybody, never actually did. And I would say that's, it was the planning that was the part that was really bothering me.

GROSS: So I'm thinking it's really lucky you didn't have a gun because if you did maybe your fears of the crowds would have gotten to you so badly maybe you would've thought it's time to shoot my way out.

CASTNER: I can - lucky, fortunate - I can understand how some guys get to the point of actually, of actually feeling it enough that they feel like they need to go through it. And I should say a lot of this is because I live in New York. My friends that live in Texas and North Carolina and other sorts of places with relaxed gun laws, most of my EOD brothers do carry a pistol everywhere they go for exactly the reasons I'm describing.

GROSS: So are they going to be angry with you for saying what you've just said and making people paranoid that maybe vets with guns are afraid of things that aren't really going to happen to them?

CASTNER: I would say that people shouldn't be paranoid because if there's two character traits that really mark my brothers, it's how competent they are and then also how disciplined.

DAVIES: Brian Castner, speaking last year with Terry Gross. His memoir, "The Long Walk," is about commanding an Explosive Ordnance Disposal unit in Iraq, and living with the aftereffects when he returned home.

More after a break. This is FRESH AIR.

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DAVIES: Let's get back to Terry's interview with Brian Castner. His memoir, "The Long Walk," is about commanding an Explosive Ordnance Disposal unit in Iraq. He uses the word crazy to describe how he felt when he returned home. He was eventually diagnosed with traumatic brain injury.

GROSS: So when you got the diagnosis of traumatic brain injury was that helpful? Now you had a name to give to some of the problems you were experiencing. Of course, it's a very frightening name. So, like, what are the ways in which it was helpful or not helpful to have a name to give to what you were experiencing, a name that said that your brain was injured in ways that you did not yet understand?

CASTNER: It was extremely helpful. I felt like I had all of these non-specific issues relating to the long-term memory, related to some of my hearing issues or sleeping issues or whatever. And I just - I thought it was all - I thought I was making it up. And my wife and I would get into so many fights about, oh, you're purposely forgetting that. Oh, we talked about this. Don't you remembering doing that?

It just caused a lot of friction in our household, on top of all of the other things we were dealing with. And to have that - you're absolutely right. Having a name helps a lot.

GROSS: I could see how she would feel if you don't remember that thing that we did together, you don't care about me. You know? Because it could be such a significant memory that you will always have that memory and cherish it.

CASTNER: It was huge, because she felt like I was choosing the war or choosing EOD over her, which is - I don't know if it's a common thing, but there's a lot of guys who do what I do who get divorced eventually because the lifestyle and the deployments are just so stressful, that you just can't maintain a marriage and a family with it.

So she felt like I was choosing the war over her, but then there was a lot of mourning that the man that she married, that she remembered, who she did all of these things with, I had changed, and I didn't even remember doing some of the things that were so dear to her.

GROSS: One of the things you used to carry with you when you were in Iraq working on the Explosive Ordinance Disposal Unit was the rosary of your dead Aunt Mary and a scapular. You say you carried those so that when you died, you weren't going to go to Hell. And how, at that time, religious were you in terms of believing in Heaven and Hell and believing that the rosary and the scapular would protect you?

CASTNER: It - so my Aunt Mary, she was a nun with the Sisters of St. Francis order here in Buffalo. And after she died, I did get her rosary, and it was her brother Paul was my grandfather. And he's the one that went to - he was in World War II, and he marched to Berlin. And he kept a journal of his travels, which is what inspired me to. And he always wore a scapular.

And I felt like carrying those two things was carrying my family with me. I also felt like if it was good enough for him, it was good enough for me. Like, I had done enough in my life that would deserve Hell, that if there is one, you know, if there's a get-out-of-jail-free card, it's worth - I've got enough space in my vest pocket to put it there.

GROSS: Where is that rosary and scapular now?

CASTNER: I still have my vest, and I have it packed away in a trunk in my basement just in case I need it, and they're still in the same flap they were then.

GROSS: How are you feeling now? I don't mean right this second, but I mean, you know.

CASTNER: I've put things in a better place, but it's never gone. My psychologist had an excellent analogy for it. She says it's like your shadow. Your shadow is always there if you look for it, but you don't always have to look at it. And really, what I was doing was staring at my shadow constantly and waiting for it to go away. And it, of course, it's never going to.

So I've learned not to look at my shadow, but - we talked a little bit before about funerals. The funeral is where I remember that the shadow is still there.

GROSS: Well, Brian Castner, I really, I want to thank you doubly. Thank you for this interview and for all you've told us. Thank you for your service to the country. Thank you very much.

CASTNER: Thank you. It's been an honor to speak to you.

DAVIES: Brian Castner's memoir is called "The Long Walk: A Story of War and the Life That Follows." It's now out in paperback and has been adapted into an opera by the American Lyric Theater. Castner spoke last year with Terry Gross. This past April Castner wrote about the reactions he received at book signings and during interviews, including his interview on FRESH AIR, to the disturbing passages in his book where he recounts his urge after returning from war to carry a gun to protect his young children.

You can find the link to that article and read an excerpt of his memoir at our website freshair.npr.org. Coming up, Maureen Corrigan reviews the new novel by Karen Joy Fowler, author of "The Jane Austen Book Club." This is FRESH AIR.